Coalition conducting operations 'heedless of their impact on civilians', with at least 933 killed in 13-month period.

The United Nations has accused a Saudi-led coalition fighting in Yemen of failing "to mitigate the impact of its operations on civilians", and said the 29-month-war had caused the spread of al-Qaeda in the country.

In a report released on Tuesday, the UN's Human Rights Council (HRC) said that between July 2016 and August 2017, coalition air attacks continued to be the leading cause of civilian casualties, killing at least 933 civilians and injuring 1,423.

"In addition to markets, residential areas, and public and private infrastructure, the past year witnessed notable air strikes against funeral gatherings and small civilian boats," the report said.

It said that "civilians may have been directly targeted", with the coalition's operations "conducted heedless of their impact on civilians without regard to the principles of distinction, proportionality and precautions in attack.

"In some cases, information suggested that no actions were taken to mitigate the impact of operations on civilians".

"I appeal to all the parties to the conflict, those supporting them and those with influence over them to have mercy on the people of Yemen," Zeid Ra'ad Al Hussein, the UN high commissioner for human rights, said.

Armed groups had exploited a power vacuum to expand their presence beyond the south and southeast of the country, the report said, with al-Qaeda now "operational" in Taiz city.

Taiz has been besieged by Houthi fighters for more than more than two and half years with al-Qaeda fighters reportedly fighting "shoulder to shoulder" with pro-government forces.

"I call on all parties to the conflict to cease hostilities and to work robustly towards a negotiated and durable solution, so that the people of Yemen may finally know peace," Al Hussein said.

Security has deteriorated in Yemen after Houthi fighters left their stronghold of Saada in the country's northwest and swept into Sanaa in September 2014.